1. Field of the Invention
The present invention relates generally to a module for receiving and transmitting optical signals and, in particular, to a module including a light transmitter, a light receiver, a beam splitter, and a connector for coupling the module to an optical fiber.
2. Description of the Related Art
A transmission and reception module, which is for use in a bi-directional optical communications network, is disclosed in European Published application 0 238 977. The transmission and reception module includes two spherical lenses which are essentially arranged at a distance from one another between a laser diode and the end of a light guide fiber, so that the spherical lenses focus the laser light onto the end of the fiber. A light ray separating means or beam splitter is arranged between the spherical lenses. Some of the light is divergently emitted from the end of the fiber in the direction of the lens farthest from the laser diode (i.e. the lens closest to the fiber) and is focused by this lens and has a wavelength different than the wavelength of the light emitted from the laser. It is this light which the beam splitter separates from the beam path and directs toward a detector or light receiver. To avoid sensitivity to deadjustment in the module, the laser diode and the lens which is closest thereto are fixed in position relative to one another on a common carrier member and are thus protected from deadjustment. At least the laser diode or the laser transmitter, the lens closest to the transmitter, the beam splitter, and the detector are mounted in a housing which may be connected to one end of an optical fiber so that the fiber end is arranged in the focus of the light of one wavelength which is stationarily defined relative to the common housing. The common housing, however, must be hermetically sealed for protection against disturbing environmental influences, particularly those which would effect the operation of the active semiconductor components (such as the light transmitter and the light receiver) mounted within the housing.